The objective of this project is to improve the safety of children sedated by nurses for diagnostic radiology by improving our understanding of the occurrence and nature of adverse events as well as understanding the influence of patient factors, provider factors and nursing practices on sedation safety. The specific aims of this study are: 1. Describe the influence of type of sedation providers (RN, MD) on safety (occurrence of unexpected adverse events) and type of adverse event when the influence of patient risk factors (age, weight, ASA class, co-existing medical conditions), procedure type and care processes (medication and monitoring type) are considered in diagnostic radiology procedures for children. 2. Determine the influence of patient risk factors (age weight, ASA class, co-existing medical conditions), procedure type, care processes (medication and monitoring type) and sedation provider type on inadequate sedation, unexpected bag-valve-mask-ventilation and prolonged sedation in children sedated for diagnostic radiology procedures. A retrospective, cross-sectional, correlational design using secondary data from the Pediatric Sedation Research Consortium will be used. Analysis of secondary data for children under 15 years of age sedated for diagnostic radiology procedures by non-anesthesia sedation providers (i.e. nurses and non-anesthesia physicians) will be analyzed to describe adverse event occurrences and provider differences, and to develop models of factors that explain adverse events. Relevance: The overall need for pediatric sedation is increasing. However, there is a gap in our knowledge regarding the safe delivery of anesthesia by nurses, including the differences in adverse event occurrences between nurse and physician sedation providers. This lack of evidence may impede future efforts to change pediatric sedation delivery processes and improve safety as resources become more limited.